Mike, you've been typing while I was writing my previous post. You can avoid using 24 panels, see previous post.
Big difference between 24V and 12V panels (beside lower cost of 24V):
1) 12v panels work with either PWM or MPPT controllers. 24V panels work MPPT controllers only, and those are more expensive.
2) 12V panels are usually small from 20W to 180W. 24V panels are from 190W and up, big and heavy.
2) 24V panels have lower amperage per same wattage, so you can use much thinner cable.
3) If you use 12V panels with PWM controller, you have to wire them in parallel, and unless it's a portable setup with very short cable, you have to use a thick cable like #6 or better.
24 panels you can wire in series and thus avoid running a thick #6 cable, BUT: this requires a better $$$ MPPT controller than Eco, and you can get away with Eco and 12V panels in parallel as described in my previous post. Buy #8 MC4 cable and you can wire 2*12V panels in parallel, and use Eco MPPT.
If you find some good 20-30A PWM controller with display, you can use it instead of Eco MPPT in the setup described above, but I don't know any. Metal body, display, and adjustable setpoints make $100 Eco attractive.
You won't find 24V panels under 190W, and with 2*190W you'll have to spend upwards of $300 for a better MPPT controller because Eco won't cut it.
